Cutter for rotary drills



4 1 1932- I c. w. ME'VI'ZGER 7 1,860,587

CUTTER FOR ROTARY DRILLS Filed Feb. 12, 1930 2 Sheets-Sheet l W W INVENTORI w V BY V V rpm, ATTORNEYS.

, CUTTER FOR ROTARY DRILLS Filed Feb. 12, 1930 2 Sheets-Sheet BY I W ja z, ATTORNEYS.

Patented May 33, 1932 will? retest":

series lreT T c GLAUDE W. EETZG'EB, 9F *H O'USTUN, Tm ASSIGNOR T .EAYNES STELLITE @QWANY, A WEEORATIQN 0E INDIANA -WTT% FOR ROTARY DBILLS Application filed Echruary 12, 1930. Serial Fro. @7585.

This inventionperteins in general to rotsry drills for deep well drilling, and 1n particular to improved cutters for such drills,

Tn rotary drills of the type to which my invention has particular reierence, two conesheped cutters having teeth on their conical surfaces are mounted on the lower end of e drillheed having. a. threaded portion at the upper end thereof by which it is attached to m the lower end of e drill line. The cutters are usually attached to the drill head so the epexes thereof lie close together new the erisoi the drill, and the lower or cutting faces of the cutters form e. linesubstantislly transverse to the axis of rotation.

During operation drills of this type are rotated in a right-handed direction so the conical cutters roll-around on the bottom of the drill hole under the weighted the drill line and the action of their cutting teeth loosens the material with which they come in contact.

it has been the custom, heretofore, to provide such conicel cutters with teeth extendso ing either longitudinally thereof along their conicel iaces, or circumferentieil "thereof eround their conical "laces. During operation such cutters exert a crushing action on the materiel with which they come in so contact, and this crushing cction soon dulls the cutters so the drill line must be raised and the cutters changed at comparatively frequent intervals, thereby. causing muchloss of time. Furthermore, the crushing action so of the chisel like cuttingteeth, and the lack of traverse tooth motion, tends to clog the cutters and impede the removal of detritus by the circulation of water employed for that purpose.

Therefore, the principal object oi the presout invention is to provide e drill cutter of the type specified having s series of continu o'us cutting edges which, in addition to the usual crushing action, have a. spiral shearto lug action tending to cut away the iormation being drilled and crowd it toward the center of the drill into the direct current of the flushing fluid used for removing the detritus.

A further object of the invention is to provide a drill cutter having cutting teeth of such form and character that their action on the formation being; drilled tends to keep their cutting edges sharp instead of making them dull and blunt as heretofore.

A still further object of this invention is to provide a cutter of the type specified that will ream or dress the bore hole during the drilling operation thereby meintoining the size and alignment thereof. w

Other aims, objects and novel features, will be apparent from the followingspeciiicstion and the accompanying illustretion, in which: t Fig. 1 is a. front view of my improved cut- I i Fig. 2 is e side viewoi the some with the lid . upper portion broken awa toshow the form of the recess therein; ,4

Fig. 3 is arear view or the seine;

Fig. 4 is a. side view, psrtisliy in section, of a drill head equipped with my improved cutters; and, I

Fig. 5 is a. diagrammatic view of thebot; tom of a bore hole showing the path or the cutting edges of the spiral teeth of my iro proved cutters thereccross. v

In the preferred embodiment oi any inven tion shown in the eccompuuyin drewin'gs, my improved cutter A is substentmlly conical in shape and formed on the conical face thereof are a plurality of continuous s irels 1 extending from the apex in e right-handed direction around the conical face to the base. The angle between adjacent sides of the spiral teeth 1 is degrees-but this single may be either greater or less for difierent kind of service. The crests 2 of the s 'irels l, which are the cutting edges, are me e sharp to increase their cutting action and, at the same time, comparatively'obtuse to increase their strength. I I

v The pitch of the spiral teeth lie two inches and the distance between adjacent crests is one half inch. The cutter shown in the i1- lustration has four spiral cutting teeth, but it is within the scope ofthis invention to employ either more or less teeth and to very provided with a beveled surface 3 which is at an angle of 90 degrees to that of the conical face. This angle, as well as that between pposite sides of the conical face, maybe varied. The beveled face 3 is provided with a plurality of teeth 4.- formed therein for the purpose of reaming or dressing the sides of the bore a hole during the drilling operation. In practice I have found that four teeth 4 on the surface 3 is satisfactory, although a different number may be used.

My improved cutter A may be of any sultable material such as tool steel, high speed steel, or a non-ferrous alloy. The cutter may also be of mild steel with the cutting edges of the spiral teeth coated with a wear resisting material such as stellite applied by means of a welding blowpipe. Furthermore, the

spiral teeth may be formed by inserting a plurality of individual sections of a wear resisting material such as tungsten carbide or hastellite. These sections may also be welded to the cutters.

The cutter A may be mounted on the drill head? by providing a recess or cavity 5 in the rear face of the cutter that fits a conical bearing member 8 threaded to a boss 10 on the head 7 and held to the cutter A by a threaded collar 9. This ineans of securing the cutter tothe drill headis well known in the art and forms no part of the invention, and this or other well known or equivalent attaching means may be employed as conditions warrant.

During the operation of my improved cutter it rolls around on the bottom of the drill hole and the cutting action of the edges 2 of the spiral teeth, 1:ZlS continuous and the path of each cutting edges 2 is from the outer edge 11 of the bore hole across the bottom toward the center 12 in the form of a spiral path 13. In addition to the crushing action of cutters of this type, my improved cutter exerts a shearing action on account of the traverse motion of the cutting edges. This traverse motion also crowds the detritus formed in drilling toward the center of the drill hole into the path of the flushing fluid thereby tending to keep the drill hole clear so the cutters can work at maximum efiiciency.

Another advantage derived from the traverse motion ofthe spiral teeth of my improved cutters is their tendency to wear on the sides thereof so they operate with great- 55 er efficiency over a longer period of time.

Various changes in the form of the cutters and in the angles forming the various portions thereof may be made, and other equivalent materials may be substituted for those specified without departing from the scope of the invention or sacrificing any of the rights thereunder.

I claim: 1. A cutter for rotary drills having a conical cutting surface provided with quadruple spiral cutting teeth having a pitch of ap proximately two inches.

2. A cutter for rotary drills having a conical cutting surface provided with a plurality of spiral cutting teeth having an angle of approximately 90 degrees between ad acent sides thereof.

3. A cutter for rotary drills havin cal cutting surface provided with a ifiurality of spiral cutting teeth having a pitch of approximately two inches and an angle of approximately 90 de ees between adjacent sides thereof, and a eveled surface ad acent said cutting surface having a plurality of cutting teeth thereon for dressing the sides of the bore hole formed by the drill.

4. A cutter for rotary earth boring drills having a conical cutting surface provided with a plurality of spiral cutting teeth thereon for removing material from the bottom of a drill hole; a beveled surface provided with a plurality of spiral cutting teeth thereon for dressing the side of said drill hole; and a wear resisting alloy forming the cutting edge of each of said cutting teeth.

In testimony whereof, I aflix my si ature.

, CLAUDE W. METZ ER.

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